Phosphonamide and phosphonamide blend compositions and method to treat water

ABSTRACT

The invention is a water treatment composition comprising at least one phosphonamide and blends thereof and a method to treat water. As phosphonamides are generally odorless, and typically solids, phosphonamide and phosphonamide blend compositions are generally odorless, conveniently processed and manufactured, and safely used without risks of exposure to odors and vapors associated with the corresponding amines. Advantageously, phosphonamides blended with amino-phosphate esters provide useful treatment compositions. The inventive compositions are generally used to treat water contained in water flow systems such as boilers and cooling towers.

RELATED APPLICATION

This application is a CIP of application Ser. No. 10/231,531 entitledPhosphonamide and Phosphonamide Blend Compositions and Method to TreatWater filed Aug. 30, 2002 now abandoned.

FIELD OF THE INVENTION

The present invention relates to a composition and method to treatwater. More particularly, the invention provides a compositioncomprising at least one phosphonamide or phosphonamide blends to treatwater.

BACKGROUND OF THE INVENTION

Water for heating and cooling apparatus must be purified or treated toavoid a plurality of problems. More specifically, boilers and coolingtowers require pure water for optimal performance. However, the watercoming into these systems is generally impure and contains contaminantswhich can foul the boiler and cooling tower.

Feed water is generally contaminated with gases, such as oxygen andcarbon dioxide. In addition, water can leach impurities from the air.These impurities lead to scale formation, corrosion, and pitting. Amajor contaminant in many water systems is iron, often leached fromwater lines.

In cooling towers, such problems may escalate due to evaporation of thewater, thereby increasing concentration of the contaminants andresulting in a higher rate of subsequent corrosion and depositiontendencies. Higher temperatures also tends to increase corrosionpotential. A longer retention time of contaminants in the water coupledwith warmer water tends to reduce the effectiveness of heat transfersurfaces and increases the potential for microbiological growth.

Currently there are a variety of different physical and chemicaltreatments for contaminated water. Conventional treatments for watersystems, such as a boiler, have included the use of amines, particularlyto scavenge oxygen and neutralize carbon dioxide. These amines aregenerally volatile having boiling points comparable to the elevatedtemperatures achieved in the boiler and generally vaporize into thesteam to treat the resulting condensate. However, amines, commonly usedto treat water, are typically commercially available only as liquids.Conventional water treatment compositions containing such amines aregenerally prepared and stored as liquids. These liquid compositionstypically emit repugnant and potentially toxic odors which may bedetected during manufacture, packaging, or shipping processes, andparticularly during the use in treating boiler water.

Corrosion inhibiting chemicals as disclosed in U.S. Pat. No. 4,066,398have been used to treat contaminated water. U.S. Pat. No. 3,510,436discloses the use of organic phosphates or phosphonates in combinationwith zinc and/or mercaptobenzothiazole for corrosion inhibition in watersystems including cooling towers. Compositions utilizing chromates andinorganic polyphosphates have been used to inhibit corrosion of metalsurfaces in contact with cooling tower water. However, such treatmentsare undesirable, both from the viewpoint of handling personnel healthand also problems associated with waste disposal. Phosphates aregenerally non-toxic. However, due to hydrolysis of polyphosphates toorthophosphates and the limited solubility of calcium orthophosphate,which is likely to form, it has been impossible in many instances tomaintain adequate concentrations of phosphates. Furthermore, from awater pollution standpoint, effluent containing a sufficiently highphosphate residual, may serve as a nutrient to aquatic life. For thesereasons, the use of chromates, inorganic phosphates and other phosphateshave been entirely unsatisfactory.

Thus, there remains a need to provide a composition to treat water inwater flow systems effectively and safely, from a health and handlingperspective, with minimal waste disposal problems.

SUMMARY OF THE INVENTION

Accordingly, the invention is directed to a composition comprising atleast one phosphonamide or blends thereof which may be added in amountseffective to treat water in water flow systems. Forming a phosphonamidefrom an amine generally eliminates odors and vapors emitted by thecorresponding amine. Accordingly, phosphonamides reduce exposure relatedhealth and safety risks to the user or handling personnel associatedwith the preparation, manufacture, packaging, and general application ofamines that have been used to treat water. In addition, the generallysolid nature of a phosphonamide, or blend of phosphonamides, typicallyallows the treatment composition to be formulated into a convenient drysolid or powder.

The phosphonamide is an amine derivativized to an amide by reacting theamine with a phosphonic acid. The phosphonamide may be fully orpartially formed depending on the mole ratios and/or weight ratios ofthe particular amine and phosphonic acid. Typically, amine to phosphonicacid weight ratios of about 1:1 to about 10:1 are suitable.

Suitable amines used to form the phosphonamide include, for example,cyclohexylamine, morpholine, octadecylamine,N,N-dimethyl-1,3-propandiamine, and ammonium hydroxide. Suitablephosphonic acids include, for example, aminotri(methylene phosphonicacid), 1-hydroxyethylidene-1,1-diphosphonic acid, and2-phosphono-butane-1,2,4-tricarboxylic acid.

Alternatively, the treatment composition may comprise a blend ofphosphonamides formed by blending together individual phosphonamides orby reacting a blend of two or more amines simultaneously with aphosphonic acid. Advantageously, non-solid phosphonamides may be blendedwith solid phosphonamides to form a solid composition. In addition,blending phosphonamides provide the advantage of improving watersolubility of the final composition thereby providing effective andeconomical water treatment.

The treatment composition may also include other components necessary totreat contaminants in the water by mixing these components with thephosphonamide. For example, an amino-phosphate ester generally formedfrom a hydroxy amine and a phosphonic acid may be blended with aphosphonamide. Additives such as a hardness control agent may also beincluded in the final composition.

The precise quantities of the phosphonamide and phosphonamide blends inthe final treatment composition added to the water may vary as desiredby the user. Concentrations will generally depend upon the desiredformulation of composition, concentration of components in the water,and the type and degree of impurities and contaminants in the water.

The present invention will be further appreciated in light of thefollowing detailed description.

DETAILED DESCRIPTION OF THE INVENTION

The invention is directed to a composition and method of treatingcontaminants and impurities in water. More specifically, the compositioncomprises at least one phosphonamide formed from an amine and aphosphonic acid. Added benefits come from blending differentphosphonamides, as well as other components, into the final treatmentcomposition. Generally, phosphonamides are odorless and solid in nature,thereby allowing the inventive composition to be a safe and convenienttreatment product. The odorless nature of the phosphonamide eliminateshealth and safety risks associated with amine odors which are oftendetected during handling, processing, and manufacture of the product.

The phosphonamide is generally formed by reacting an amine with aphosphonic acid to affect a corresponding covalent amide bond. The amineused to form the corresponding phosphonamide may be any primary orsecondary amine. For example, without limitation, the amine may have ageneral formula HN—R¹R², where R¹ and R² are independently selected fromthe group consisting of H, alkyl, cycloalkyl, aryl, and heteroarylorganic structures having up to 10 atoms selected from the groupconsisting of C, N, and O. The term “alkyl” as used herein, generallyrefers to a straight or branched hydrocarbon chain of varying length ornumber of atoms, such as from 1-10 atoms. The term “cycloalkyl”, as usedherein, refers to an unsaturated cyclic ring comprising carbon,nitrogen, or oxygen atoms in the ring. The term “aryl”, as used herein,refers to an aromatic ring consisting of carbon atoms, and the term“heteroaryl”, as used herein, refers to an aromatic ring havingheteroatoms including nitrogen and oxygen. Alternatively, R¹ and R²taken together with a nitrogen to which they are attached, may form a 5-or 6-membered ring containing 0-2 additional heteroatoms selected fromnitrogen or oxygen. For example, morpholine, a cyclic amine wherein R¹and R² taken together forms a 6-member ring containing an oxygen atom atthe 4-position, may be used to form a phosphonamide for the treatmentcomposition. In addition, the R¹ and R² substitutions may bear otherfunctional groups, such as ethers or amines, which do not participate inthe amide bond formation.

Examples of suitable amines include, but are not limited to,cyclohexylamine, octadecylamine, and N,N-dimethyl-1,3-propanediamine,and even ammonium hydroxide. The amines may be purchased commerciallyfrom vendors such as Aldrich Chemical Co., or synthesized as desired, tooptimize physical and chemical properties of the resultingphosphonamide.

A variety of phosphonic acids and derivatives thereof may be used toreact with the amine. Persons of ordinary skill in the art readilyunderstand that the term “phosphonic acid”, as used herein, generallyrefers to phosphonic acids having different general formulae which mayreact with an amine to produce a phosphonamide. For example, aphosphonic acid having the general formula (OR)₂—P(O)OH wherein the Rgroups may be identical or different, is suitable for the invention.Alternatively, a phosphonic acid having a general formula (OH)₂—P(O)ORis also suitable. Thus, a phosphonamide formed from an amine and aphosphonic acid of the former formula will have a general structure:(OR)₂—P(O)N—R¹R², whereas, a phosphonamide formed from an amine and aphosphonic acid of the latter formula may have a general structure:RO—P(O)—(N—R¹R²)₂. Suitable phosphonic acids for use in the inventionmay be commercially purchased or synthesized depending upon desiredproperties of the final treatment composition. Examples of suitablephosphonic acids include, but are not limited to, amino tri(methylenephosphonic acid), 1-hydroxyethylidene-1-1-diphosphonic acid, and2-phosphono-butane-1,2,4-tricarboxylic acid.

The phosphonamide may be purchased commercially, if available, orsynthesized using conventional synthetic methods and reagents necessaryto form the amide bond. For instance, the phosphonamide may be formed bymixing the amine and phosphonic acid together using conventional mixingapparatus and methods. For example, the amine, in desired molar orweight quantities, may be first added to a powder blender. The blendermay then be activated while a phosphonic acid, in desired molar orweight quantities, is added to the amine. Depending on the class andstructure of the amine and particular phosphonic acid, reaction of theamine with the phosphonic acid may be sufficiently exothermic to formthe amide bond. Alternatively, heat or catalysts may be utilized tooptimize the reaction and provide maximum conversion of the amine andphosphonic acid to the corresponding phosphonamide. With mostphosphonamides, as the amide bond forms, the reaction mixtureprecipitates to generate a solid phosphonamide product. The resultingphosphonamide is then cooled and processed by conventional techniques toeliminate by-products and catalysts, if any, and to purify thephosphonamide. Particularly useful phosphonamides include, withoutlimitation, phosphonamides formed from amines reacted with1-hydroxyethylidene-1-1-diphosphonic acid, and2-phosphono-butane-1,2,4-tricarboxylic acid respectively.

It is desirable and economical, for optimal water treatment and solidformulation, to use a composition comprising a blend of more than onephosphonamide. The term ‘blend’ as used herein, is intended to mean amixture or combination of more than one component, such as aphosphonamide. Phosphonamide blends facilitate formation for a solidtreatment composition while optimizing the level and specificity oftreatment by utilizing different amines. In addition, phosphonamideblends have the advantage of minimizing or eliminating hygroscopicity ordeliquescence of a treatment composition where one phosphonamide ismildly hygroscopic in nature, i.e., tending to absorb moisture overtime, thereby posing a risk to the stability of the phosphonamide andthe overall treatment composition. For example, blending anon-hygroscopic phosphonamide with a mildly hydroscopic phosphonamidemay provide a phosphonamide blend composition which is stable, resistantto absorption of moisture, and has a long shelf life. In one embodimentof the invention, the treatment composition comprises a blend of atleast two phosphonamides formed from different amines reacted with aphosphonic acid.

In addition, blending phosphonamides may provide the advantage ofimproving the water solubility of a final treatment composition whichmay include a non-water soluble phosphonamide. One factor influencingthe water solubility of a phosphonamide is the hygroscopicity ordeliquescent nature of the phosphonamide discussed above. Watersolubility may be improved by blending desirable hygroscopic ordeliquescent components, such as desired phosphonamides, in quantitiesresulting in a composition having greater solubility characteristics.For example, blending a non-hygroscopic phosphonamide with a liquid orsemi-solid component, such as an amino-phosphate ester, discussed inmore detail further below, may improve water solubility of the finalcomposition.

Blends of phosphonamides may be prepared by combining more than onephosphonamide, each prepared individually, and blending them together.Alternatively, blends of phosphonamides may be prepared by mixingdifferent amines, i.e., amines having different R groups, together in ablender, adding a single phosphonic acid to the mixture of amines, andcausing the mixture to react to form a mixture or blend of differentphosphonamides. For example, a mixture of two or more amines in desiredmolar quantities may be blended with a desired phosphonic acid.

The molar or weight ratios of the amines to phosphonic acid should be inthe range of about 1:1 to about 10:1. An amine to phosphonic acid moleratio of equal to or greater than 1:1 will generally allow completeconversion of every amine to a corresponding phosphonamide. In oneembodiment of the invention, the blend has an amine to phosphonic acidmole ratio ranging from about 3:2 to about 4:1 to provide adequate watertreatment. Persons of ordinary skill in the art readily understand thatsome phosphonic acids, depending upon the general formula discussedabove, may utilize two molecules of amine per molecule of phosphonicacid to form a phosphonamide. For instance, a phosphonic acids havingthe general formula (OH)₂—P(O)OR may react with two molecules of anamine to form a phosphonamide having two moles of the amine per mole ofphosphonic acid. In this case, the corresponding phosphonamide may becompletely formed where the amine to phosphonic acid mole ratio is atleast 2:1.

The amount of the phosphonamide, or blends thereof, used to effectivelytreat water will depend upon the user and other factors such as thelevel of the impurities and contaminants in the water, the desired waterconcentration of the phosphonamides, and the desired formulation of thefinal composition. Effective concentrations of the phosphonamide in thewater may generally vary. For example, in a steam boiler, theconcentration of the phosphonamide should be in the range of 1-200 ppmfor effective treatment of water, and 1-200 ppm for effective treatmentof condensate in the boiler feed lines.

To obtain such water concentrations, sufficient amounts of thephosphonamide composition must be added to the water. The precise amountwill depend upon the particular phosphonamide concentration in thecomposition. The phosphonamide may generally be present in thecomposition in at least about 10% by weight of the final treatmentcomposition. Water may be more effectively treated where thephosphonamide concentration is higher. Where the composition includes ablend of two or more phosphonamides, it is beneficial to have eachindividual phosphonamide present in at least about 10% by weight of thefinal composition. In one embodiment, the treatment composition includesmorpholine-1-hydroxy-ethylidene-1-phosphoryl-phosphonamide, present in arange of about 10% to about 50% by weight, andcyclohexylamine-1-hydroxy-ethylidene-1-phosphoryl-phosphonamide, presentin a range of about 10% to about 66% by total weight of the aminecomponent in the final composition.

Further aspects of the invention include phosphonamides blended withother components to beneficially treat water. One such component is anamino-phosphate ester. Amino-phosphate esters are particularly useful intreating water at elevated temperatures, such as boiler water andcondensate, as the amino-phosphate ester generally degrades at theelevated temperature, at atmospheric or slightly higher pressure torelease the hydroxy amine and the phosphonic acid into the water.Amino-phosphate esters, depending on the amine, are generally liquids.

Amino-phosphate esters may generally be formed from a hydroxy amine anda phosphonic acid. The hydroxy amine may be any hydroxy aminecommercially available from vendors, such as Aldrich Chemical Co., orsynthesized. Hydroxy amines can be synthesized by modifying an aminecore molecule to attach the requisite terminal hydroxy group.Conventional methods to incorporate the hydroxy terminus includingconversion of a terminal functional group to a hydroxyl group may beused. Such methods are disclosed in Advanced Organic Chemistry, 4^(th)Ed., authored by Jerry March, published in 1992. Examples of suitablehydroxy amines for the amino phosphate ester includeN,N-diethylethanolamine, 2-amino-2-methyl-1-propanol,1,1-dimethylamine-propanol, and 2-dimethylamino-2-methyl-1-propanol.

Suitable phosphonic acids used to form the amino-phosphate estersinclude, without limitation, those suitable for forming thephosphonamides discussed above. Preparation of the hydroxylamine-phosphonic acid ester may be accomplished by synthetic methods asknown to persons skilled in the art. For example, the preparation ofamino phosphate esters is described in U.S. Pat. No. 3,477,956 and U.S.Pat. No. 3,528,502.

Blends of phosphonamides and amino-phosphate esters may be prepared bymixing a plurality of amines, including one or more hydroxy amines, witha phosphonic acid in desired molar ratios or weight percent toeffectively form the corresponding phosphonamides and amino-phosphateesters. For example, in one embodiment of the invention, the compositionincludes a blend ofmorpholine-1-hydroxy-ethylidene-1-phosphoryl-phosphonamide,cyclohexylamine-1-hydroxy-ethylidene-2-phosphoryl-phosphonamide, anddiethylaminoethanol-1-hydroxy-ethylidene-1-phosphoryl-phosphate esterwherein each phosphonamide is present in the composition in at leastabout 10% by weight, and the amino-phosphate ester is present in atleast about 10% by weight of the amine. In preparing this blend, thecumulative amine to 1-hydroxy-ethylidene-1,1-diphosphonic acid moleratio is generally in the range of about 1:1 to about 10:1.

Such phosphonamide-amino phosphate ester blends provide advantageouscompositional properties and water treatment qualities. As discussedearlier, blending one or more phosphonamides with one or moreamino-phosphate ester may provide the advantage of optimizing thepossibility of a solid composition where one component is hygroscopic oressentially a liquid in nature. Depending upon the precise weight ratiosof non-deliquescent components relative to the deliquescent components,the blended composition may be formulated into a convenient solid. Forexample, a blend of a mildly hygroscopic morpholine-HEDP amide and aliquid diethylaminoethanol-HEDP ester, with a non-hygroscopiccyclohexylamine-HEDP amide provides a composition which may be a solidwhere the weight ratio of cyclohexylamine-HEDP amide is about or greaterthan 25%.

Furthermore, such blend compositions advantageously improve watersolubility of the final treatment composition, thereby improving theeffectiveness of the water treatment. For instance, a blend ofmorpholine-HEDP amide, cyclohexylamine-HEDP amide, anddiethylaminoethanol-HEDP ester in the right proportions may have a watersolubility of 50 weight percent per volume of water or greater. Forexample, a blend formed from a mixture of morpholine in about 13-14% byweight, cyclohexylamine in about 32-33% by weight, anddiethylaminoethanol in about 54% by weight, was reacted with1-hydroxy-ethylidene-1,1-diphosphonic acid at different cumulative amineto 1-hydroxy-ethylidene-1,1-diphosphonic acid mole ratios ranging fromabout 3:2 to about 4:1 produced blend compositions having advantageouswater solubilities in the range of from about 45% to about 80% soluble.In a case where a desirable blend composition has marginal watersolubility, then a larger amount of the composition would have to beadded to effectively treat the water.

Additional components which may be added to the inventive compositioninclude, without limitation, additional oxygen scavenging agents,alkalinity control agents, hardness reducing agents, corrosioninhibiting agents, carbonic acid neutralizing agents, and ironcontrolling agents. These components may be formulated with thephosphonamides, along with amino-phosphate esters, to form an all-in-onetreatment composition by the addition of concentrated forms of eachcomponent at relative concentrations to allow the formulated treatmentcomposition to be dispensed into the water to attain the desired useconcentrations. The actual amount of each component added to theconcentrated formulation generally depends on, among other factors, theprecise intended use concentrations and the concentration of eachcomponent as purchased. For example, in one embodiment, a sulfonatedwater soluble polymeric hardness control agent, such as Versiflex 1,commercially available from Alco, Inc. may be added in about 10% toabout 50% by weight of the final composition to reduce hardness in thewater.

The inventive water treatment compositions are also useful for treatingwater in cooling towers. The particular treatment composition willgenerally vary depending upon the quantity of water, the temperature ofthe water, and the level of contamination. For example, in oneembodiment, a cooling tower treatment composition includes aphosphonamide formed from mixing a cyclohexylamine with1-hydroxyethylidene-1,1-diphosphonic acid, and having an amine tophosphonic acid mole ratio of from about 2:1 to about 10:1. Thisphosphonamide has the advantage of being a solid. Generally, coolingtower water may be effectively treated if the phosphonamide is added inan amount to obtain a water concentration in the range of 1-20 ppm.

In one composition particularly suited for cooling tower water is thereaction product of cyclohexylamine and HEDP. The ratio of amine to HEDPshould be in the range of from about 1 to 1 to about 10 to 1. Further,cyclohexylamine in about 33% by weight and1-dihydroxyethylidene-1,1-diphosphonic acid in about 37% by weight, canbe combined with a copolymer, which may be a liquid, in about 30% byweight, to form a solid. Such a blend has minimal or no hydroscopicityand has a prolonged shelf life while maintaining the solid form.Examples of polymers which may be combined with a phosphonamide to treatwater in cooling towers include, without limitation, polyacrylate.

Accordingly, the invention is a composition and method of treating waterby adding an amount of a phosphonamide or blends thereof to treat thewater. The phosphonamide may be applied as a concentrated liquid, a drypowder, or as one of many components in a treatment compositionformulated as a concentrated liquid or, more preferably, as a drypowdery solid. Phosphonamides do not produce pungent odors typicallyassociated with amines. Furthermore, they provide a solid which can beadded to boilers and cooling towers to provide an amine and a phosphate.

While the present invention has been illustrated by a description ofvarious embodiments, and while these embodiments have been described indetail, it is not the intention of the applicants to restrict or in anyway limit the scope of the appended claims to such detail. Additionaladvantages and modifications will readily appear to those skilled in theart. Therefore, the invention in its broader aspects is not limited tothe specific details and representative methods as shown and described.Accordingly, it is apparent that certain modifications or alterationscan be made without departing from the spirit or scope of the inventionset forth in the appended claims.

1. A method of treating water in a flowing water system selected fromthe group consisting of boilers and cooling towers to treat impurities,which can foul the boiler or cooling tower, comprising the step of:adding to water a composition comprising at least one phosphonamideformed from a reaction between an amine and a phosphonic acid, in anamount sufficient to treat the water, wherein the phosphonamide is anamine derivativized to an amide by said reaction.
 2. The method claimedin claim 1 wherein the amine is of the general formula HN—R¹R² whereinR¹ and R² independently are selected from the group consisting of H,alkyl, cycloalkyl, aryl, and heteroaryl organic structures having up to10 atoms selected from the group consisting of C, N, and O, and whereinR¹ and R² taken together with the nitrogen to which they are attachedcan form a 5 or 6 membered ring containing 0-2 additional heteroatomsselected from N or O.
 3. The method claimed in claim 1 wherein the amineis selected from the group consisting of cyclohexylamine, morpholine,octadecylamine, N,N-dimethyl-1,3-propanediamine, and ammonium hydroxide.4. The method claimed in claim 1 wherein the phosphonic acid is selectedfrom the group consisting of aminotri(methylene phosphonic acid),1-hydroxyethylidene-1,1-diphosphonic acid, and2-phosphono-butane-1,2,4-tricarboxylic acid.
 5. The method claimed inclaim 1 comprising adding to the water a blend of at least twophosphonamides formed from different amines and a phosphonic acid,wherein said blend has a cumulative amine to phosphonic acid mole ratioin the range of from about 1:1 to about 10:1.
 6. The method claimed inclaim 5 wherein each phosphonamide is present in at least about 10% byweight of the composition.
 7. The method claimed in claim 1 furthercomprising adding to the water an amino-phosphate ester formed from ahydroxyamine and a phosphonic acid.
 8. The method claimed in claim 7wherein the amino-phosphate ester is present in at least about 10% byweight of the composition.
 9. The method claimed in claim 7 wherein thehydroxyamine is selected from the group consisting ofN,N-diethylethanolamine, 2-amino-2-methyl-1-propanol,1,1-dimethylamine-propanol, and 2-dimethylamino-2-methyl-1-propanol. 10.The method claimed in claim 1 further comprising adding to the water ahardness control agent.
 11. The method claimed in claim 10 wherein thehardness control agent is a sulfonated water soluble polymeric compound.12. The method claimed in claim 1 wherein the phosphonamide is presentin at least about 10% by weight of the composition.
 13. The methodclaimed in claim 1 wherein the composition is a solid.
 14. The methodclaimed in claim 1 wherein the composition is added to boiler water totreat water in a boiler and boiler feedlines.
 15. The method claimed inclaim 1 wherein the composition is added to water in a cooling tower.16. The method claimed in claim 1 comprising adding to water an amountof a blend of: at least two phosphonamides formed from at least twodifferent amines selected from the group consisting of cyclohexylamine,morpholine, octadecylamine, N,N-dimethyl-1,3-propanediamine, andammonium hydroxide, and a first phosphonic acid; and an amino-phosphateester formed from a hydroxyamine selected from the group consisting ofN,N-diethylethanolamine, 2-amino-2-methyl-1-propanol,1,1-dimethylamine-propanol, and 2-dimethylamino-2-methyl-1-propanol, anda second phosphonic acid, wherein the blend has a cumulative amine tocumulative amine to phosphonic acid mole ratio in the range of fromabout 1:1 to about 10:1.
 17. The method claimed in claim 16 wherein thefirst acid is the same as the second acid.
 18. The method claimed inclaim 16 wherein the first and second phosphonic acids are independentlyselected from the group consisting of aminotri(methylene phosphonicacid), 1-hydroxyethylidene-1,1-diphosphonic acid, and2-phosphono-butane-1,2,4-tricarboxylic acid.
 19. The method claimed inclaim 1 comprising adding to water an amount of a blend of: amorpholine-1-hydroxy-ethylidene-phosphoryl-phosphonamide formed frommorpholine present in a range of from about 10% to about 50% by weightand 1-hydroxy-ethylidene-1,1-di-phosphonic acid; acyclohexylamine-1-hydroxy-ethylidene-phosphoryl-phosphonamide formedfrom cyclohexylamine present in a range of from about 10% to about 66%by weight and 1-hydroxy-ethylidene-1,1-di-phosphonic acid; and adiethylaminoethanol-1-hydroxy-ethylidene-phosphoryl-phosphonate esterformed from diethylaminoethanol present in a range of from about 10% toabout 70% by weight and 1-hydroxy-ethylidene-1,1-di-phosphonic acid,wherein the cumulative amine to 1-hydroxy-ethylidene-1,1-di-phosphonicacid weight ratio is in the range of from about 1:1 to about 10:1. 20.The method claimed in claim 19 wherein the blend is added to boilerwater to treat water in a boiler and boiler feedlines.
 21. The methodclaimed in claim 1 comprising adding to water in a cooling tower: acyclohexylamine-1-hydroxy-ethylidene-phosphoryl-phosphonamide formedfrom cyclohexylamine and 1-hydroxy-ethylidene-diphosphonic acid andhaving a cyclohexylamine to 1-hydroxy-ethylidene-diphosphonic acid moleratio in the range of from about 1:10 to about2:1, and a copolymer, inan amount sufficient to treat the water.